Synthesis and Reversible Li-intercalation Behavior of BaFeO₄ films

Abstract

Barium iron oxide containing hexavalent iron (Fe^VIO₄²⁻) was directly synthesized on iron substrates by anodic oxidation using Ba(OH)₂ solution. The lithium (de)intercalation properties were investigated using X-ray diffraction, X-ray photoelectron spectroscopy, high-resolution transmission electron microscopy, and electrochemical charge/discharge measurements. A 45 nm thick BaFeO₄ film exhibited a discharge capacity of 300 mAh g⁻¹, which is close to the theoretical value of 313 mAh g⁻¹ calculated from the three electron reaction between iron VI and III states.